The proper motion of PSR J1550-5418 measured with VLBI: a second magnetar velocity measurement

TL;DR

This study measures the proper motion of magnetar PSR J1550-5418 using VLBI, finding a moderate velocity that challenges theories linking high magnetic fields to extremely high birth velocities.

Contribution

It provides a second measurement of magnetar velocity, showing that high magnetic fields do not necessarily correlate with very large natal kicks.

Findings

Proper motion of PSR J1550-5418 is 9.2 mas/yr.

Transverse velocity is approximately 280 km/s.

Magnetar velocities are moderate, not extremely high.

Abstract

The formation mechanism of neutron stars with extremely large magnetic field strengths (magnetars) remains unclear. Some formation scenarios predict that magnetars should be born with extremely high space velocities, >1000 km/s. Using the Long Baseline Array in Australia, we have measured the proper motion of the intermittently radio-bright magnetar J1550-5418 (1E 1547.0-5408) to be 9.2 +/- 0.6 mas/yr. For a likely distance of 6 +/- 2 kpc, the implied transverse velocity is 280 + 130 - 120 km/s after correcting for Galactic rotation. Along with the ~200 km/s transverse velocity measured for the magnetar XTE J1810-197, this result suggests that formation pathways producing large magnetic fields do not require very large birth kicks.